Theory and Design of Air Cushion Craft

Liang Yun Deputy Chief Naval Architect of the Marine

Design & Research Institute of China

Alan Bliault 5hell International Exploration and Production

Hollan

A member of the Hodder Headline Group LONDON

Copuhlibhcd in North, Central and South America by John Wilcy & Sons Inc.. New York . Toronto

Contents

duction to hovercraft Hovercraft beginnings ACV and SES development in the U K ACV and SES development in the former USSR IJS hovercraft development ACV and SES development in China SES and ACV developments in the 1990s Applications for ACVISES The future SES and ACV design

2. Air cushion theory 2.1 Introduction 2.2 Early air cushion theory developments 2.3 Practical formulae for predicting air cushion performance 2.4 Static air cushion characteristics on a water surface 2.5 Flow rate coefficient method 2.6 The 'wave pumping' concept 2.7 Calculation of cushion stability derivatives and damping

coefficients

3. Steady drag forces 3.1 Introduction 3.2 Classification of drag components 3.3 Air cushion wave-making drag ( R , ) 3.4 Aerodynamic profile drag 3.5 Aerodynamic momentum drag 3.6 Differential air momentum drag froln leakage under bowlstern

seals 3.7 Skirt drag

viii Contents

3.8 Sidewall water friction drag 3.9 Sidewall wave-making drag 3.10 Hydrodyna~nic ~noinentum drag due to engine cooling watcr 3.11 Underwater appcndagc drag 3.12 Total ACV and SES drag over watcr 3.13 ACV skirtlterrain interaction drag 3.14 Problems concerning ACVlSES take-off 3.15 Effect of various Factors on drag

4. Stability 4.1 lntroduction 4.2 Static transverse stability of SES on cushion 4.3 SES transverse dynamic stability 4.4 Calculation of ACV transverse stability 4.5 Factors affecting ACV transvcrsc stability 4.6 Dynamic stability, plough-in and overturning or hovercraft 4.7 Overturning in waves

5. Trim and water surface deformation under the cushion 5.1 lntroduction 5.2 Water surface deforination inlbeyond ACV air cushion over

calm water 5.3 Water surface deformation inlbeyond SES air cushion on

calm water 5.4 Dynamic trim of ACVlSES on cushion over calm water

6. Manceuvrability 6.1 Kcy ACV and SES manceuvrability factors 6.2 Introduction to ACV control surfaces 6.3 Differential equations of motion for ACV manceuvrability 6.4 Course stability 6.5 ACV turning performance

7. Design and analysis of ACV and SES skirts 7.1 lntroduction 7.2 Development and state of the art skirt configuration 7.3 Static geometry and analysis of forces acting on skirts 7.4 Geometry and analysis of forces in double or triple bag stern

skirts 7.5 Geometry and forces for othcr ACV skirts 7.6 Analysis of forces causing the tuck-under of skirts 7.7 Skirt bounce analysis 7.8 Spray suppression skirts 7.9 Skirt dynamic response

8. Motions in waves 8.1 Introduction

Contents ix

8.2 Transverse motions of SES in beam seas (coupled roll and heave) 8.3 Loilgitudinal SES motions in waves 8.4 Longitudinal motions of an ACV in regular waves 8.5 Motion of ACV and SES in short-crested wmes 8.6 Plough-in of SES in following waves 8.7 Factors affecting the seaworthiness of ACVISES

9. Model experiments and scaling laws 9.1 Introduction 9.2 Scaling criteria for hovercraft models during static hovering tests 9.3 Scaling criteria Tor tests of hovercraft over water 9.4 Summary scaling criteria for hovercraft research, design and tests

10. Design methodology and performance estimation 10.1 Design methodology 10.2 Stability requirements and standards 10.3 Requirements for damaged stabiliiy 10.4 Requirements for seaworthiness 10.5 Requirements for habitability 10.6 Kequirements for manauvrability 10.7 Obstaclc clearance capability

11. Determination of principal dimensions of ACVISES 11.1 The dcsign process 11.2 Role parameters 11.3 Initial weight estimate 11.4 First approximation of ACV displacement (all-up weight),

and estimation of weight in various groups 11.5 Parameter checks [or ACVISES during dcsign 11.6 Determination of hovercraft principal dimensions

12. Lift system design 12.1 Introduction 12.2 Deterinillation of air flow rate, pressure and lift system power 12.3 Design of fan air inletloutlet systcms 12.4 Lift fan selection and design

13. Skirt design 13. l Introduction 13.2 Skirt damage patterns 13.3 Skirt failure modes 13.4 Skirt loading 13.5 Contact forccs 13.6 Selection of skirt material 13.7 Selection of skirt joints 13.8 Assembly and manufacturing technology for skirts 13.9 Skirt configuration design

X Contents

14. Structural design 14.1 ACV and SES structural design features 14.2 External forces on hull introduct ion to the strength

calculatio~l of craft 14.3 Brief introduction to the structural calculation used in

MARIC 14.4 Calculation methods for strength in the former Soviet Union 14.5 Safety factors 14.6 Considerations for thickness of plates in hull structural design 14.7 Hovercraft vibration

15. Propulsion system design 15.1 Introdnction 15.2 Air propcllcrs 15.3 Ductcd propellers and fans 15.4 Marine propellers 15.5 Waterjcts 15.6 Power transmission 15.7 Surface contact propulsion

16. Power unit selection 16.1 lntroductio~l 16.2 Powering estimation 16.3 Diesel engines 16.4 Gas turbines 16.5 General design requirements 16.6 Machinery space layout 16.7 Systems and controls 16.8 Operation and maintellancc

Index

Page numbers in bold rzfcr to figures and page numbers in italic indicate tablcs.

AALC 150 50 !node1 350 Acceleration 124, 468 Acceleration/frequency tolrrat~on limits 369 Accidents 185

ACVs 13 hovercrat-t 13, 13, 14

Accommodation space requirements 399 ACV

accidents 13 applications 41-5 calculation ol' transverse stability 163 8 .

166-8 development in UK 9-21 dimensions of 386-7, 389-YO dynamic trim 190 Factors affecting transverse stability

168-72 longitudinal motion in regular waves for

308 22 manceuvrability 206 moving over deep water 190 3 operation modes over ground terrain 122 over shallow water 1 9 6 6 water surfacc deformation inlbeyond air

cushion over calm water 190-3 weight of 389-90

Aerodynamic force and momcnt 221, 223 Aerodynamic momentum drag 96 Aerodynamic profile drag 95-6, 96 Aerodynamic yawing moment 226 Air clearance 50, 62, 65

characteristic curves 424 Air cushion 2, 42

adiabatic stiffness coefficient S48

charactcristics 72 characteristics curves 70. 71 craft, classilication 6 flow rdtc due to mass change rate of S01 pcrfortnance

on rigid surface 51 prediction 55-65

pressure distribution 472, 472 stability 76-83 supported vehicles, see ACV system 2824. 299-301, 313-17 theory 48-83

early developments 50 5 Air duct 70, 71,424

calculation 410-12 charactcristics 78 configuration 413 loss coelficicnt 411 non-dimensional charactcristic curves

345-6 non-dimensional characteristics 350 system 412,413 valves 2 16

Air flow coellicient 64 Air tlow rate 1334, 339,340

coefficient 149 determination 407 10 distribution effect 339

Air gap 83,128 Air inlet

inclination angle 417 of integrated liftipropulsior~ systems 414 pressure losses 414

Air jet momcnt from cushion to atmosphere 286 7

Air jet propulsio~~ 5 0 6 7 Air jet strean~lines 54

Air leakage 79 flow rate of 300, 3 14 1 5 under SES sidewall 67

Air lubricatio~l 2-3, 9. 48 Air propellers 507 14

blade erosion and its mitigation 514-15 blade types and efliciency 5 0 9 10 construction 513 diamctcrltip speed relationship 51 1 selection 510, 51 1 weight 51 3

Air propulsors 21 1-14 Air rudders 217 Air streamlines 55 Air supply to bow skirt arca 328 Aluminium alloy 459 Amphibious capability 41,48 Amphibious hovercraft 1, 3, 4.4, 274 Anti-plough-in

hydrofoils 327 requirements 453

Anti-roll systems 335-6 Anti-spray plate 335 Anti-submarine vessels 41, 42 AP1.RR 15, 20, 21. 40. 41, 213, 507, 520, 592,

594 API .88400 44 Aprons 271 Archirnedes' principle 66 Arctic transport 45 Axial flow pumps 559

Bag and linger bow seal 247 Bag and finger bow skirt 153,247,249 Bag and finger skirt 49. 52, 55, 59, 62. 71.

129,238,243. 262,451 equations for static geometry and force

analysis 251 5 forces aclirig on 263 model tests 250-1 static geometry 250-7 supporting forces acting on joints 25L7

Bag and nozzle skirt chain connection lor 237 flexible diaphragm connection 237

Bag and periccll skirt 243, 244, 261 Bag chord length 251 Bag cushior~ pressure ratio 63, 262 Bag pressure 59 Bag skirt 49 Bag stern seal 248

Index 619

Bag stern skirt, geometry and analysis of forces in douhlc or lriple 258-60

Bag to cushion pressure ratio 62, 65. 251 coefficient 60

Beam seas, difkrential equations of coupled roll and heave motion o l SES in 291

Rearings 571 Bell Aerospace Corporation 25, 29 Bcll-Halter Corporation 29 Bell Tcxlron Jeff (B) 599 Bending 469 Bending moment 470. 470, 471

acting on midship section 469-70 cushion-bornc operation 470 hull-borne operation 471 transverse 471

Bernoulli cquation 53,412, 495 Bernoulli theory 67 BH.7 14, 15.239 BH.11029 30, 29 Blade element theory 499-500. 501, 524 Blade velocity vector diagram 496 Bliss, Demlis l l , 233 Blohm and Voss 40 Boundary layer thickness 54 Bow acceleration 307 Bow finger tip linc 327 Bow hydrofoils 3334.334 Row seal during take off, watcr contact

phenomenon of 105 Bow skirt

etnergencc 302 tuck-in 326

Bow skirt area air supply to 328 relative to stern 327

Bow skirt finger tip 258 Rowistern acceleration. frequency response

for 32 1 Bowistern seal

and basc-line gap 149 during heeling, righting moment of 155 equipment 326-7 heave stiffness for 328 relative gap 150

Bowlstcrn seal drag 102 3 BA. Kolczacv method 103 MARIC method 102 Rin-lchi Marao mcthod 103

Bowlstern seals 246-9 interaction 188

620 Index

Bowlstern skirts. height determination 453 Brodrene Aa 3 9 4 0 British Hovel-craft Corporation 10 Britten-Norman 12

Cabin 370, 373 volu~ne 41 2

Captured air bubble 2 3. 246 Cargo vessels 40 Catamarans l , 42-3, 113 Cavitation 522 4. 523, 531. 537, 545. 561

water jets 556 7 Cavitation tunnel 552 Centrifugal fans 4259, 507

aerodynamics characteristics 426 Centrifugal pumps 558 CG 359,359,461,463,464,469, 564 China. ACV and SES dzvelopment 32-9 Chong Cheng Shipping Company 35 Cirrus 39 Cohblcstnnc effect 322, 323, 324 Cockerell. Sir Christopher 3, 7, 9. 48, 233,

275 C:oeHicient f SO Coefficient of addcd mass 278 Cocfficicnt of clongation 347 Commercial design parameter5 378 Co~npuler program for dilrerential equations

of rnolion 290 Constant cushion volume 74 Constr~~ction cost per unit seat 398 Contact forces 441 - 2 C:ontinuity equation of Iiow 282 Control equipment 208 Control surfaces 207-17

fcatures 21 6 state of the art 2 1 6 17. 216

Control bystem colnponeiits 563 Controllable pitch air propellers (ducted

propellers) 21 1-13 Coordinate system 297-8, 298, 308, 309 Correction coefficient of wetted surface 109 Correction coefficient of wetted surface arca

of sidewalls 110 Couplings 571 Coursz-keeping ability

and handling 374 under qua~.tcring or beam winds 375

Course stability 224-7 analysis 225-7 dynamic 225

static 224-5 vertical fins for 208. 209 see also Stability

Cushion air compressibility 321, 322-3 How rate and pressure 71

Cushion altenualion coefficient vs. craft spccd 465

Cushion-hornc uper d I ' lon bending nmlnent 470 in high wews 3 3 6 8

Cushion compartmentation l63 4. 169,170 Cushion depth, damping effect of 323 C:ushion dcpthfbcam ralio 359 Cushion flow coefficient 401 Cushion llow 1-ate 334 Cushion fluw rate coefficient 62 Cushion force 214-16, 222-3, 284 Cushion geometry 49 Cushion height 359 Cushion heightlwidth ratio versus transvel.sc

roll stiffness 360 Cushion lcngtbibeani ratio 87. 101, 132,

150-1, 330-1,332,357,400 Cushio~l lift power coefficient 62 Cushion mome11t222 3 . 284 Cushion pi-cssure 41, 50, 5940, 73, 79, 80,

89 analysis of forces acting on fingers under

264 and heave amplitude R1 during plough-in 326 tluctuations 277. 324 spatial distribution 278 trends 401

Cushion prcssure coefficient 60, 62 Cushion pressure distribution 472, 473

\S. ship speed 181 Cushion przssurcllengtl~ ratio 89, 132, 149.

400 Cushion pressure ratio 344 Cushion stalic prosure 506, 506 Cushion system fans 507 Cushion wave-making drag 98 Cushioncraft CC1 12 Cushioncraft CC2 12 Cushiollcraft CC5 12, 507

Damping coelficienl 7 6 83, 278 calculation 77-80 cxperimer~tal methods 80 2

Index 621

I i

Damping effect of cushion depth 323

l on seaworthiness 333-5

Dcck area 41-2 Deck plates, dcsign load 473

l de Laval, Ciustav 2 Dcsign 4 6 7

concepts 190 1 inertial loads 461-3 leading particulars selection prior to 402 loads 469

i I lnethodology 353-5

I parameters 354, 377. 378-9 checks during design 397 9 process 377 sequence 377

! Detachable bowistcrn scals 249 Lliaphragms 251

installation 451 of D-shape bags 264 5

Diesel engines 579,581, 588-96 cooling systems 590-4 exhausts 595 lubrication system 595 maintenance 610-1 1 number of engines and layout 588-90.589 operation 607-10 reliel' valves 595 vibration 5 9 4 5

Differential air momentum drag from leakage under howlstern seals 97

Differential equations of couplcd roll and heave motion in beam seas 291

i ! DilTerential equations of longitudinal

nlotion in wavcs, block diagram 297. 305 Differential equations of motion 223 4,

281-90. 304-7, 317-18 con~putcr program Sor 290 formation 219-20 in regular waves 313

Dimcnsions determination 354, 377404 limitations 399 of ACV 386 7. 389-90.403

Disc loading 498 Displacement, ACV 384-97 Docking. strcngth calculation 473 Drag

components, classification 84-5 forccs 84-134 in head seas 338

in waves 338 of non-flush sca-watcr strainers 116 17 of rudders 1 15-1 h of shafts (or quill shafts) and boss I l h of strut palms 116 over calm water 120, 130 srr nlsu llydrodynamic drag: Kesidual

drag; Seal dn->*g; Skirt drag; Total drag: Wave-making drag

1~)ragIweight ratio 94 Drivcr tcchniquc 185 D-shape hags 184,184,25 1

diaphragms of 2 6 6 5 DTNSRDC 28 Duct system characteristic 3 2 3 4 Ilucted falls 515-20

duct dcsign 518-19 fan selection 5 17 stators 518

Ductcd propcllcrs 21 1 13. 507. 515 Ducted propulsors 274. 520 Dynamic motions 273-341. h04

historical rcvicw 2 7 4 6 Dynamic transverse righting moment of SES

159 Dynamic trim 156

on cushion over calm water 200 4,201 over calm water for ACV 308-12 prediction over calm water 200-3

Elastic n~odulus 347 Electrical cquipmcnt, wcight of 396 Elevons 208-10 Energy equation 141 Enginc

cooling water, hydrodynamic momentum drag due to 115

lhilurc modes and clkcts 606 heating for suh-zero temperatures 584-5 monitoring and control systern 6U8 operating characteristics 581-2 power ranges 579 starting 605 systclns and controls 607

Equations of motion 217 Equilihrium equation

US lbrccs 265 6 static forces 309-10

Euler number 344 Extended szgment skirts 245, 244. 260 External air stream lines 180

622 Index

External fol-ccs on hull 461-5 External response 327

Fan air duct characteristic 323 charactcristic equation 310

Fan air inletloutlet system 413-19 Fan blade regulation 21 6 Fan characteristic cquatiotl 142 Fan charactcristic~ 284 Fan curve gradient 327 Fan flow rate 172 Fan inlet

loss coefficient 412 pressure recovery coefficient at 412 system 413-17

Fan outlet system. SES 419 Fan overall pressure 412-13 Fan speed 148 Fans

aerodynamic characteristics 423 air How rate 430 centrifugal 425-9, 507 cushion system 507 efficiency-flow rate characteristics 431 horizontal arrangement 418-19 HVAC systems 423 impellcr diameter 428-9 noise reduction 430 non-dimensional characteristic curves

345-6 non-dimensional characteristics 350 off-design operation 422 overall pressure-tlow rate characteristics

431 overall pressure head 410 13 pressure-How characteristic curve 430 selection of type 420 5. 421 by means of specific speed 426-8 vertical arrangement 418 see also Ducted fans; Lifl fans

Fast Attack SES 44 Fast vessels 42 Fatigue endurance of transmission shafts

569-7 1 Finger bow skirt 247 Finger height ratio 454 Finger inclination angle 454 Fins 217 Flagellation 437 Flat lilt fan 323 4

Flexible bow seal 135 Flexible bowlstern seal 153 4 Flexible skirt 11, 28, 47-9. 52, 56, 91, 100,

127, 173,232,235 advantages 232 development 233

Flow coefficient 407, 408 Flow continuity equation 78. 141

for small perturbations 315-17 Flow modes in heaving motion 77. 78 Flow rate

air lcakage 300 air leakage and cross-llow, small

perturbation equation Cor 314 15 coefficient 49, 71-3. 345 continuity equation 310-12 due to mass change ratc of air cushion

301 equation 141 minimum calm water drag 409-10

Flow rate-pressurc head linear equation with small perturbation 313-14

Flullering 437 Foil-shaped appendages l l S Footprint pressure 41 France 40 Frequency response

bowistern acceleration 321 cushion prcssure 293 heave acceleration 292,319 heave amplitude 318-19,318 heave motion 77 pitch amplitude 319-20. 319. 333 roll amplitude 293 wave exciting force 320 wave exciting moment 320

Froude Krilov hypothesis 276-7,296 Frotide number 85, X7,91.92, 102, 103, 109,

110, 115, 177,181, 196,338, 348-9 and wiwe profile 189

Froude scaling relationship 342 Fuel and oil, weight of 396 Fuel consumption 397-8 Fuel filtering 606 Fucl system 505

Gap height 12.1 Gas turbines 579,583, 596-603,597,602

air intake filtration 601-3, 603 air intake How requirements 600 alarms 605

inflow distortions 600 layout and engine sclcction issues 598-9 maintenance 610 l l noise 603 operation 610 protection from foreign object damage

600-1 Gearbox 572-3,575

power flow diagram 574 Generators 595 Geometrical dimensions 297-8, 298, 308, 309 Germany 40 Goldstein factor 525, 526 Corko~~rhunin 127 GriKon Hovercraft 25 GRP 38,38, 39,459 Guide wheels on laud 210-11,211

Habitability requirements 365-74 Halter Marine Inc. 29 Harbin Shipbuilding Engineering Institute

(HSEI) 32,48 HD-I 12 HD-2 194 Head winds, performance 341 Hezt generation 28 Heave 273 Heave acceleration, frequency response 292,

319 Heave amplitude 75, 80

and cushion pressure 81 frequency response 318-19.318

Heave attenuation system 335-6 Heave displacement 81 Heave frequency 80 Heave motion 76, 76. 81, 306, 341

flow modes in 77,78 frequency response for 77

Heave position 83 Hcavc stability 80, 83

derivatives calculation 77-80 experimental methods 80-2

Heave stiffness for howlstern seals 328 Heave velocity 8 1. 83 HEBA high efficiency fan 431-2 Heeling 138, 141

angle 361-2 moment 361 regulation using weight of persons and

water (oil) ballast 215

restoration moment 145 restoring moment during 223 righting arm 147 righting moment of howlstern seal during

155 with air cushion compartmentation on

rigid surface 164 with air cushion compartmcntation on

waler 164 without air cushion compartmentation on

water 164 High-performance marinc vehicles,

classification 2 High-speed marine vehicle typcs I HM-2 14-15,20, 330, 356,408

bow scal 17 glass reinforced structures under

construction 16 stern seal 17

HM-5 20 HM-218 16 HM-221 18 Holland 40 Horizontal air rudders 20810 Hovercraft

accidents 13, 13, 14 classification 6 future 45-6 historical background 1 4 principal particulars for carly Chinese and

British 7 see alro ACV: SES

Hovercraft Development Ltd 10, 11, 275 Hovering damping 76-83 Hoverlloyd 16 Hovermarine Limited 14, 18 Hull

design 185 efficiency 544 external forces on 461-5 strength of 464 structural design 474. 476 weight of 393, 397

Hull-borne operation, bending moment 471 Hump drag 132 Hump transition speed 364 HVAC 515 Hydrodynamic coel'ficients 222 Hydrodynamic drag 274

due to engine cooling water 115 see ulso Drag

624 Index

Hydrodynamic forces and moments 221-2 acting on sidewalls 285-6. 295, 303 acting on skirts 294, 301-3 acting on stern seal 303

Hydrodynamic resistance 1, 178 Hydrofoil patrol boat (PHM) 32 Hydrofoils 42, 43

anti-plough-in 327 Hydrostatic pressure acting on bottom and

sidewalls 473 Hyperbolic distribution 89

Ice breaker 45 Inducer pumps 559 lnllatable diaphragms, tenlion calculation

252 lti~ier draft 132, 133 Inneriouter water lints 126 lnncrloutcr watcr surfaccs 188 Insulation 370 Internal air stream lines 180 Internal wave profiles 177 Italy 40

Japan 40 JEFF(A) 25.164,241,436,463 JEFF(B) 25,96,463 Jct cxtcnsions 49 k t velocity 498 Jetted air rudder 208 Jcttcd bag typc skirt 235 .Jetted extensiotis 128 Jetted nozzle skirts 236 Jcttcd skirt 127 .Iin Snh River 5. 35

3K-SES 28 Kaario, Toivio 3 Korea 40

LACV-30 26 Laplace transformation 317 LCAC 25-6.43. 241. 507 LCAC-001 207 LCG 94, 130-2, 130, 131, 185 LEBED 23 LHD-4 26 Life-saving equipment. weight of 395 Lift drag 185

ratio 134 Lift fans 2 8 2 4

balancing 429 basic data 427 characteristics at small flow rate 429 impellor speed and diatllctcr 429 installation 430, 430 prcssure-llow or 296 selection and design 420 32 statistics 427 tcchnical issues 429-32

Lift power 51, 54 5_ 148 output coefficient 65 versus air inlet location 415

Lift system design 406-32 distribution of pressure 406 ducting problems 326 insufficieticy 326 layout 406 powcr 412 13 simulated pressure distribution 411

Lining situation, strength calculation 473 Limiting roll angles versus relative cushion

height 362 Limiting atress design 564 Liquid load 396 7 Load transporters 45 Local loading 471-2 Longitudinal ccntrc of gravity; see LCG Longitudinal metacentric height 356 60 Longitudinal motion

in rcg~tlar wavcs for ACV 308-22 it1 waves 296307

principal parameters 298 Longitudinal stability kccl (LSK) 139 LSD-I 26

M10 44 Machinery

control 604-5, 604G.5 space layout 606

Maticeuvrability 205-31 ACV 206 - ~

basic assumptions and nomenclature 218, 218. 219

diflerential equations of motion 217-24 fcaturcs of ACVISES 205-6 key factors 205-7 on ice 376 rcquirzments 374-6

MARIC 3, 33-8, 56, 62, 84, 88, 102, 104-6, 111. 117. 119, 125, 143,465-7

Index 625

Marine Design & Research Institute of China. xec MARlC

Marine propellers bladc pitch 529 blade sections 521 design 520-37 efficiency 520 example propeller and shaft layouts for

SES 533 fbr SES 535-6 installation 521 K, and Ku diagrams 53U sclcction proccdurc 526 31, 528 types 522

Market development 17-22 Matzrials 28 Mayer velocity distribution 54 MCM 31-9,44

dctail dcsign and construction 3 1 2 primary design 31

MCMH 31,40 MCR (Maximum Continuous power Rating)

577 Medium sized patrol SES 32 MEKAT 40 Metacentric height

longitudinal 356-60 transverse 356-60. 3.58

Military applications 43 4 Military design parameters 378 Military SESiACV 32 Military transport vehicles, time interval

from invention to first application Y Mine countermeasures 11. 30-9 Mine swccpcrs 41 Mixed flow pumps 558 Model 711 127, 173 Modcl711 3 138 Model 71 1-1 33,33, 235, 236 Model 711-11 34. 34,214.257.441 Modcl 71 1-111 34, 34,326, 327 Model 713 189, 327 Model 716 36 Model 71641 37.37 Model 717 35, 145, 151,151, 188, 189 Model 717-71 36, 356 Model 717-111 356 Model 717A 156. 158 Model 717C 121, 130, 131, 156, 158, 159,

160, 357 Model 719-11 36

Model 719 433 Model 719-11 43,460 Model 7202 35 Model 7203 36 Model 7205 199 Model experiments 342-52 Moment of inertia 463 Momentum exchange principle diagram 496 Momentum theory 97,493-8, 524, 548-55 Motion pumping 274 Motion standards 360 Motions in waves 273-341

characteristic features of ACV and SES 2768

historical review 2 7 6 6 key craft paranlctcrs 278 short crested waves 3 2 2 4

MTBO (Mean Time Between Ovzrhaul) 577 Multi-bag stern skirt 247 Multi-cell skirt system 165 Multiple engines 579-81 MVPP5 15,19,226 MVPP15 15

NACA 16 scrics 524 NACA h3 series 51 9 NACA 66 series 524 National Rcscarch Dcvclopmcnt

Corporation 10 Needham, C.H. Latimer 11.232 Nct positivc suction hcad (NPSH) 544, 547,

561-2 Newton's formula 53 Noise

fans 430 gas turbines 603 lzvcls 369-72. 370, 372 4. 372 water jets 539, 540

Non-flush sea-water strainers, drag of 11G17 Norway 3 9 4 0 Nozzles 546-7

elevation 547

Obstacle clearance capability 375, 376 Oil exploration 22, 39 Oil field applications 4 6 5 Open loop and segment skirt 243, 261 Operating modes 136 Outline design procedure 535 Ovcrdll propulsive efficiency (OPC) 538, 554,

562

626 Index

Overturning 173-85. 175. I82 and yawing angles 183 at high speed 177 85 at low speed 176 in waves 185-6 measures for improving resistance to

183 5 principal reasons 18&3 SR.N6 186

Parabola-shaped sidewalls 114 Parabolic water plancs 114 Passenger accommodation 42 Passcnger ferries 44 Patrol vessels 40 Payload factor 397 Payload fraction 38493 Peripheral Interfacc Module (PTM) 609 Peripheraljct air cushion 50-1 Peripheral jet hovercraft 48 Pitch

amplitude, frequency response 319-20, 319,333

angle 306 damping 333 4 exciting moment 307 motions 340-1

Pitching 273 Planing craft 1,42 Planing stern seal 154 Plate thickness in hull structural design 474,

476 Platforming 7 3 4 , 74

analysis 7 4 6 Pleasure craft 44 Plenum chamber

cushion 8. 52 on rigid surface 5 1-2 theory 72

Plough-in 173-85, 174, 182, 325 at high speed 177-85 boundary 181

SR.N6 186 cushion pressure during 326 in following waves for SES 324-8 internal reasons 326 7 measures for improving resistance to

183 5 methods for prevcnting 327-8 principal reasons 180-3 progression 178-80, 179

test dala 180 see al ,~o Anti-plough-in

Position determination 220-3 Post-hump spced 374 Power augmented ram wing (PARWIG) craft

5-9,6 Power consumption

in head winds and waves 406 per ton-knot 20

Power loss with increased temperature 5 8 4 5 Power pcr unit seat 398 Power plant

limitations 399 weight of 395 6

Power transmission 564-73 design criteria 564-~6

Power unit selection 577-61 1 design requirements 604-6

Powering estimation 585-7, 586, 587 Pressure coefficient 345, 462 Prcssure-flow of lift fans 296 Pressure head equation 283 Pressureilength ratio 86, 87 Propulsion devices, turning tracks ibr 229 Propulsion system 28, 37, 37, 41, 42

design 487-576 ACV 487 basic theories 492-504 methodology 508-9 SES 488-92

PUC-22 592 Puff ports 213-~14. 214, 231 Pump

characteristics. types and selection 555-6 eficiency 559

Quill shafts, drag due to 116

Radial flow pumps 558 Ram air pressure recovery 417 Range determination 399 Recreation design parameters 379 Reduction drives 572-3 Relative air gap 65 Relative initial static transverse metacentric

height 148-9.148, 149,150 Relative sidewall thickness 1489, 148 Relative transvcrse righting arm 150 Remote monitoring 604-5, 604-5 Residual drag 84-5

coellicient of sidewall 115

Index 627

Restoring moment during heeling 223 Retractable water rudder 210. 210 Reversing gcar 562-3 Reynolds law 342 Reynolds number 100, 104, 344,345,349 Ride characteristics 367 Ride control system (RCS) 30, 336, 336, 337 Ridz quality 43 Righting moment of howlstern seal during

heeling 155 Rigid body dynamics 277 Rigid bow seal l35 Role naramcters 378-9 Roll amplitude, frequency response curves

for 293 Rolling 273, 280, 285

stiNness 359 Rolling angle and craft speed 178 Rolls-Royce 'Marine Proleus' gas turbine

englnes 13 Rotatable nozzles 562 Rotating ducted thrusters 213 Rotating thruster unit 508 Rotation derivatives 220-3 Rudders 208-1 1

drag of 115-16 Running attitude 156 9, 158

Safety factors 4734. 474, 475 Saunders-Roe Limited 10, 11 Scaling criteria 351

during static hovering tests 343-8 over water 348-52

Scaling laws 342-52 Sea Action Group (SAG) 44 Seakeeping quality 43 Seal drag 121

coefficient 103 Seasickness 368 Seaspeed 16 Seaworthiness 90, 273-4, 321, 32841,454

effcct of principal dimensions 33&3 key observations 33941 requirements 3645, 399 scaling conditions 352

Service speeds 43 SES

applications 41-5 dynamic transverse righting moment of

159 location of inlets and appendages 188-90

plough-in in following waves for 3 2 6 8 static transverse stability on cushion

137 52 transverse dynamic stability 152 63 water surcace deformation inlbeyond air

cushion on calm water 197-200, 198 SES-100 86 SES-100A 27,27,28, 30, 85,85. 175, 337 SES-100B 27, 28 SES-200 30, 30, 39, 86, 336, 336 Shafts and boss, drag due to 116 Shallow watcr drag 91 Shanghai Hu Ilong Shipyard 35 Shaw, R.A. 10 Shear forces 471 Sidewail 109

air leakage 280, 281-2 chines 335 configurations 66 depth 333 depth ratio 400 draft 280, 281-2 geometric configuration 145-8 hydrodynamic forces and moments acting

on 285-6, 295,303 inner draft 333 thickness 66, 357 thickness ratio 332-3, 4 0 2 4 wetted surface of 110

Sidewall hovercraft 4, 5 development in UK 9 22

Sidcwall water friction drag 104-10 B.A. Kolezaev method 109 MARIC method 104-6 mcthod used in Japan 106-8, 108 NPL method 109

Sidewall wave-making drag l 11-14, 113 B.A. Kolezaev method 114 equivalent cushion beam method 11 1-13 Hiroomi Ozawa method 1 13-14

Single wall theory 52-5 Skirt

abrasion and corrosion 434 abrasion force 441 air feed holes 449-50 assembly and manufacturing technology

449 51 attachments 449 bounce analysis 267-70,268,269,270 clearance 79, 82, 171 coating 439, 4465, 444

628 Index

Skirt (contd) cumponcnts, force acting on 264 contact drag 277-8 damage patterns 433 4 deformability 455 deformation 242 delamination 4334, 438 drag ibrcc 44 1 dynamic response 271-2 effect on seaworthincss 328 30 Ihilurc modes 435-6, 435 gcometric features 451. 452 ground interference drag 124 hydrodynamic foi-ces acting on 294, 301-3 impact force 442 manufacture flow chart 450 observation under water 238 pressure drag 10 1-2 processing 450 service l ik 433 shifting installation 215 shifting system 165 stiKness 455 systcni 184 tailoring 449-50 tearing 434 tcst boxes 343 test rig 5 6 8 , 5&9. 59. 60 total drag 99 luck-in at bow skirt 326 tuck-under 261-7 tuck-under boundary 453 type cffcct on seaworthiness 329-30 wave-making drag coellicicnt 101 weight 265-7, 396 weight pcr unit area 346, 349-50 with extended flexible nozzle 236

Skirt analysis 232. 452-7 forccs acting on 262-3 forces analysis for deformed fingcrs 266 hydrodynamic forccs acting on skirts

running on water 265 Skirt bag

D-type 184, 184 tension acting on curved sections 262

Skirt configuration 53, 134, 165, 233, 233, 242-5,244,245, 249.250 amphibious ACV 235 42 BH.7 241 design 451-7 development 235 49

evolution 235 S R N 6 241 state of the art 23549

Skirt design 232, 433~57 main issues 234

Skirt drag 98-103, 124 Skirl drag coefficient 134 Skirt fingers 436, 439, 441, 442, 442. 445. 450

inward inclination angle 454 Skirt force (morncnt) 284 Skirt friction drag 99-101 Skirt geometry 453

design 323 clastic deformation and hysteresis etTect

250-1 Skirt height 328-9, 359

and cushion beam ratio 358 ratio 400-1 statistics 356

Skirt joints, selection 447-9, 447, 448 Skirt lift apparatus 214-15. 215 Skirt loading 437-41, 437

prcssure force 437 vibration forces 437

Skirt material 64, 64, 347 open wcavc cloth 443 selection 442-7 specific weight 44.5, 446 tension and tear strength 443 test facilities 440 thickness effect 330

Skirtiterrain intcraction drag 121-3 SKMR-I 25,463 Slamming 1. 46G7

forces in wavcs 364-5 Slipstream jet velocity 497 Small waterplane thin hull vcsscls (SWATH) 1 S-N curve 569.570 Speed

degradation 330, 331, 341, 364 delerrnination 399 improvement 332

Spray suppression skirts 270-1, 272, 456 7 SK.N1 7.7. 10. 11,48-9, 507 SR.N2 11, 13 SR.N3 11, 12, 13 SK.N4 11. 12, 13. 14, 16, 17, 239, 330, 330,

331, 331. 333, 361, 368, 418, 441, 463, 520 drag and thrust curves 119 skirt configuration 240

Index 629

SR.N5 13,76, 173 SR.N6 13, 14.15, 86, 173, 174. 176, 214,361,

418 overturning 186 plougli-in boundary 186

SR.N6-012 185 Stability 135 86

acceptable 137 and cushion height

ACV 355 SES 356

coordinate system of craft l67 criteria and standards for stability of SES

stability in turns 162 stability in wavcs 162 static stability 161-2

damagc requirements 363 design requirements 355 62 dynamic stability of ACV travelling ovcr

watcr 173 effect of fan flow rate on transverse

stability 01- ACV 172 eflect of stability skirt clearancc on

transverse stability 171 effect of various parameters on transvcrse

slability 14&51 in waves 364 internal stability skirts 190 longitudiiial stability trunks 456 rcquirements 399

for large hecling angles 361-2 skirt configurations 261 standards 355-62 static transversc i~lltial stahility of ACV

360 static transverse stability of ACV l69 static transversc stability on cushion

137-52; 143 static transverse stability without LSK

141-2 transversc dynaiilic stability 152-63 transverse stability 358

as function ol' Froude number 177 during lake-off 159-61 effcct of VCG 171-2 factors affecting ACV 168-72 for ACV 163-8 in waves 161 on cushion in motion 154 9 with flexible bowlstern seals 154-5 with rigid stern seal 155-6

without cushion compartmentation 1 70-1

transverse stability moment of hcclcd SES al spccd 160

transverse stability trunks 456 Standing's formula 197 Static air cushion characteristics on water

surface 66-71 Static air cushion performance of ACVs on

water surfilcc 68-71, 68, 69 Slatic hovering performancc of SES on water

66-8 Static hovcriiig tests 343-8 Static thiust 5 0 1 4 Stator systems, design 518 Steel 459 Stern bag skirts, geometric parameters 259 Stern double planing bag 247 Stern planing rigid seal 247. 249 Stern scal 12S-9. 154

hydrodynamic forcc acting on 303 with air bag 248,248

Stern skirt, pressure distribution acting on inner surface 260

Streamline analysis 60-2 diagram 61

Strength calculation 461 Strength of hull 464 Strouhal number 346 Structural design 458-86

ACV 459 60 current state 460 features 458-60 hull 474, 476 SES 459

Structural strength analysis. former IJSSK 467-73 calculation 465-7

Strut palms, drag of 116 Subcavitating propellers 520. 526 Subsystem design 354-5 Supercavitating propcllers 522, 531-7

outline dcsign procedure 535 Supports 571 Surface contact propulsion 5 7 6 6

design considerations 574-6 Surhcc cffect ships (SES) I Sway 273 Swivelling pylons 211, 212 Systems 28

630 Index

Tacoma Marine Industries 40 Take-off 1249, 159-61

dynamic stability during 127 holes 71 performance 72 water contact phenomenon of how seal

during 105 TCG 162 Teeth 271 Thornycroft. Sir John 1. 2 Thrust

deduction 544 in head seas 338

Thrustllift ratio 181 Torsion 469 Torsion load 470, 470 Torsional stress 564 Total drag 85

of ACV model 71 1-IIA 118 of ACV model 7202 118 over water 1 17-21

ACV 117-19, 117,118 SES 119 21

skirt 99 Total system weight 577-9, 578 Transmission configuration 5 8 2 ~ 4 Transmission shaft

design factors 566 design load case matrix 568 design stresses 566-8 fatigue endurance of 569-71 sections for analysis 567

Transport eficiency 397 Transverse metacentric height 162, 356-60.

158

Transverse motions of SES in beam seas 279-94

Transverse righting moment 160,295 Transverse roll stiffness versus cushion

heightlwidth ratio 360 Transverse shift of ccntrc of cushion area

165-6, 165,166 Trim 187-204

angle 181, 182. 185 calculation 153 4 factors influencing 188 prediction above hump speed on calm

water 203-4 regulation using weight of persons and

water (oil) ballast 215 TSL-A 600.601

Tuck-under 267 Turning diameter 374 Turning pcrformancc 227 31 Turning tracks

between bank and non bank turn 230 for propulsion devices 229

Twin bag skirt 154, 451

UH-15P 502 UK 9 21 ,40 Underwater appendage drag 115-17 US 25-32

amphibious craft 25 surface effect ship development 26-30

USSR (formcr) 22-5,22-3 Utility applications 44 Utility craft 45, 590 Utility design parameters 378-9

VA.1 to 3 series 11 Variable depth sonar (VDS) 32 Variable-pitch ducted fans 516 Variable-pitch propeller hub construction

and controlsystem 514 VCG171 2 Velocitv streamlines 501. 502 Vertical acceleration 320, 335. 336. 365-8,

366,367 Vertical fins for course stability 208, 209 Vertical rudder 208, 209 Vessel trim 604 Vibration 28, 31, 368, 47686

absorption 478-82 acceptahle levels 480 analysis 479 assessment 485 critical operational frequencies 484 damping 370-2

design 481 detail design phase 4 8 3 ~ 5 diesel engines 5 9 6 5 during construction 485 exciting force 482 high operational speed 477 TSO 2372 and I S 0 3945 standards 4 7 ~ low natural frequency 476 malfunctions caused by 477 permissible rules 482 preliminary design phase 482-3 severe and supcrharmonic excitation

source 476

1

Index 631

tests and trials 486 watcr jets 540

Vickers 12 Vortex theory 524 6 Viya,ycur 96 VT.2 14, 15

Waban Aki 45 Wake factors 544 Warner, D.K. 3 Watcr contact plienomcnon of bow seal

during take-off 105 Water jets 537 64

advantages 538 cavitat~on 556-7 efficiency 492,521, 522, 548 54,549,551,

557 flush-type inlet 538 geometries 541 inlet losses 544 6 inlet velocity 560-1 inlet with sccondary slow specd intake 546 integrated control systems 5 6 3 4 KaMcWa 522 noise 539, 540 overall propulsivc cficiency (OPC) 538,

554, 562 performancc 540-1 physical dimensions 540 prcssure effects around intake 553 selection 543, 550, 559-62 steering 562 3 tlirusl vs. craft speed 558 vibration 540 weight vs. inlet diameter 562, 563

Watcr propulsor types 491 Water surfacc deformation 189, 192

at inboard profile 194 HD-2 194 inlbcyond ACV air cushion over calnl

water 190 6 iniheyond SES air cushion on calm water

197-200. 198 Water surface profile 192 Wavc amplitude 1 9 6 7 Wave equation 298-9, 312 Wave exciting force, frequency response ibr

320 Wave exciting moment, frequency response

for 320 Wave height 338,340

Wave impact force distribution 472-3 loading coefficient 462 presrul-e 463-5,464

Wave interference 323 Wave-making drag 86-93, 90, 91.92, 94, 94,

97 coefficient 88, 8 9 , 9 6 5 coeflicient of slender sidcwalls 114 influence of water depth 92 ratio 91

Wave-making drag-lift ratio 89 Wave profilc

and Froude number 189 bcyond cushion, 1ilodel7205 199 inloff cushion due to moving rectangular

air cushion 193 Wave pumping 274, 278

concept 49,73-6 motion 74. 74 rate 75-6

WD-901 37.37, 3 8 , 189 WD-902 38 Wcapon systems 32, 42 Weber number 100, 349 Weight

components 379 80 distribution 38.5. 388 equilibrium equation 142 of ACV 389~90,403 of air propellers 51 3 of deck equipment and painting 3 9 3 4 of electrical equipment 396 of equipment 394 of fuel and oil 396 of hull 393, 397 of life-saving equipment 395 of mctallic structure 393 of power plant 395-6 o f ship systems 395 of skirt systcm 265-7, 346. 349 50, 396 of water-jet unit 562, 563 vs, displacement 394

Weight classilication former USSR 381-2 high-speed boats 382 4 MARIC 380 USSR 381 Western countries 382

Weight estimate 379-84 checklist 391-2

632 Index

West, A A . 52-5, 63 Wing in ground ell'cct machines (WIG and Wcstland AircraSt Limited 1 1 PAKWIC;) I . 5 9 . 6 Wetted surlhcc Work boats 45

corrzction coefficierlt o l 109 of sidewalls 104. 106. 107, 110 XR-I 138

Wetted hurlhcc area, correction coefficient XR-IA 26, 26 107, 108 XR- I D 30

Wetted surface5 188 XR-S 29 Whirl speed 568 9 Wind direction and speed 228 Yaw 92. 9 6 5 . 273 Wind tunnel model lcsts 347 Yawing angles and overturning 183 Wind tunnel tcsts 343